A USD800 CPU

[WiredBrain]

I'm planning to buy new system next week. My budget is around USD800 for only the CPU. I haven't decide whether to buy an AMD-based or Intel-based system. The main factor will be price/performance ratio. I'm a casual gamer and don't intend to overclock. I also would like it to be not too noisy. These are my rough specs:

AMD-based
X2 AM2 4600+
XFX XXX 7600GT
Corsair DDR667 1GB
Motherboard [any recommendation?]
WD 250GB - 300
Liteon DVD-burner
CM Extreme 430W [any recommendation?]

Intel-based
C2D E6400
Motherboard [max=Gigabyte DS3]
Same as above

If possible, I would like PSU+casing to be less than USD85. Another thing, I would most probably[if at all] upgrade the graphic card after about 2 years. Is it wiser to be SLI-ready or just replace it with a new card when the time comes? Will 7600GT will still be around by then? This will greatly affect the choice of motherboard.

Someone recommend Gigabyte DS3. Is there something similar but cheaper? I don't mind it being non-overclockable as long as it's reliable. I'm also planning to add my old IDE hdd in addition to the new SATA hdd. Thus, IDE connectors and USB ports are important too.

I need advice and suggestions for the components particularly motherboard and PSU. Thank you.